Function soreceive_stream

freebsd/kern/uipc_socket.c:2392–2609

* Optimized version of soreceive() for stream (TCP) sockets. */

 * Optimized version of soreceive() for stream (TCP) sockets.
 */
int
soreceive_stream(struct socket *so, struct sockaddr **psa, struct uio *uio,
    struct mbuf **mp0, struct mbuf **controlp, int *flagsp)
{
	int len = 0, error = 0, flags, oresid;
	struct sockbuf *sb;
	struct mbuf *m, *n = NULL;

	/* We only do stream sockets. */
	if (so->so_type != SOCK_STREAM)
		return (EINVAL);
	if (psa != NULL)
		*psa = NULL;
	if (flagsp != NULL)
		flags = *flagsp &~ MSG_EOR;
	else
		flags = 0;
	if (controlp != NULL)
		*controlp = NULL;
	if (flags & MSG_OOB)
		return (soreceive_rcvoob(so, uio, flags));
	if (mp0 != NULL)
		*mp0 = NULL;

	sb = &so->so_rcv;

#ifdef KERN_TLS
	/*
	 * KTLS store TLS records as records with a control message to
	 * describe the framing.
	 *
	 * We check once here before acquiring locks to optimize the
	 * common case.
	 */
	if (sb->sb_tls_info != NULL)
		return (soreceive_generic(so, psa, uio, mp0, controlp,
		    flagsp));
#endif

	/* Prevent other readers from entering the socket. */
	error = sblock(sb, SBLOCKWAIT(flags));
	if (error)
		return (error);
	SOCKBUF_LOCK(sb);

#ifdef KERN_TLS
	if (sb->sb_tls_info != NULL) {
		SOCKBUF_UNLOCK(sb);
		sbunlock(sb);
		return (soreceive_generic(so, psa, uio, mp0, controlp,
		    flagsp));
	}
#endif

	/* Easy one, no space to copyout anything. */
	if (uio->uio_resid == 0) {
		error = EINVAL;
		goto out;